JPH0241593Y2 - - Google Patents

Description

[Detailed explanation of the invention] "Industrial application field" This invention is a reverberation system that transmits wave pulses such as radio waves or ultrasonic waves, receives the reflected signal, and displays it, such as in radar and sonar. The present invention relates to a coordinate conversion display device used in a detection device to perform so-called polar coordinate detection and to display a display in rectangular coordinates, that is, a display in which the display surface is horizontally and vertically scanned.

``Prior Art'' A conventional coordinate conversion display device of this type stores the sine value and cosine value corresponding to the detection azimuth angle in separate read-only memories (hereinafter referred to as ROM ), and the read sin and cos values are cumulatively added for each unit of detection distance, and the detection signal is stored in the main memory using these cumulative addition values as addresses, and the main memory is horizontally The data was read out and displayed in synchronization with the scanning of the vertical scanning display.

In this way, in the past, sine values and cosine values were stored in separate ROMs. By the way, a single ROM commercially available has a considerable storage capacity, and even if it stores the sine and cosine values required for the coordinate transformation, there is still a considerable amount of unused space left over.

The purpose of this invention is to provide a coordinate conversion display device that stores sine and cosine values using one ROM and can effectively utilize the ROM.

``Means for solving the problem'' According to this invention, the sine and cosine values of each angle in each detection direction are alternately calculated.
Using the information sequentially stored in the ROM, the angle memory is read twice for each wave pulse transmission for the angle corresponding to the receiving direction of the wave pulse at that time. That is, the sine and cosine values corresponding to the angle are read out, and the read out sine and cosine values are cumulatively added.

``Example'' Hereinafter, an example of the coordinate conversion display device according to this invention will be described with reference to the drawings. FIG. 1 shows an example in which this invention is applied to a radar device. The direction of directivity of the directional antenna 11 is repeatedly rotated by, for example, a motor 12. Transmission trigger generator 13
The transmitter 14 is driven by a trigger signal from the antenna 11, and the transmitter 14 transmits pulsed radio waves from the antenna 11 in the direction of the antenna. The reflected wave of the pulse radio wave is received by the receiver 15 through the antenna 11, and is amplified and detected. Its detection output is
sampled at a constant period by the AD converter 16,
Each sampled value is converted into a digital value, for example a one-bit or multi-bit digital signal. The converted digital signal is stored in buffer memory 17. Immediately after the trigger signal is transmitted from the transmission trigger generator 13, the distance counter 18 counts the built-in clock.
Writing to the buffer memory 17 is performed using the count value of the distance counter 18 as an address. Further, sampling is performed by the AD converter 16 for each clock.

In this example, a trigger pulse is generated from a pulse based on the directional direction at every fixed angle of rotation of the directional direction of the antenna 11. That is, the angle pulse generator 19 is driven by the rotation of the motor 12, and the angle pulse generator 19 generates pulses as shown in FIG. 2A, for example, every 0.17 degrees. At each rising edge of this pulse, a trigger pulse 21 is sent to the transmitting trigger generator 13 as shown in FIG. 2B.
It is generated by This trigger pulse causes a pulsed radio wave to be emitted as described above, and the received and detected output of the reflected signal is obtained as the reflected signal 22 as shown in FIG.
It is converted into a digital signal in the converter 16, and 256 sample values, for example, are stored in the buffer memory 17. This sample pulse occurs immediately after the transmission trigger pulse 21, as shown in FIG. 2D, and ends before the next transmission trigger pulse occurs. This sampling period is changed depending on the distance of the detection radar, the so-called detection range. Distance counter 18 is in a reset state and starts counting with an internal clock from the trailing edge of trigger pulse 21, and ends the counting operation after counting, for example, 256 times. This distance counter 1
The conversion output of the AD converter 16 is written into the buffer memory 17 using the count value of 8 as an address.

On the other hand, a scanning type display 23 is provided, which is composed of, for example, a cathode ray tube display or the like, and displays images by horizontally and vertically scanning the display surface, similar to a television receiver. The display surface of the display 23 is subjected to horizontal and vertical raster scanning by the display control section 24. In synchronization with this raster scanning, an X address indicating each point on each scanning line is generated by the read address generator 25, and an address indicating the horizontal scanning line is generated by the Y address generator 26. These X address generator 25 and Y address generator 26
is constituted by, for example, a counter, and is generated in synchronization with the scanning in the display control section 24. These X address and Y address are given to the main memory 27 as read addresses, and the main memory 27 is repeatedly read out, and the read output is supplied to the display 23 as a display signal. In this case main memory 2
If the output of 7 is multiple bits, it is converted to an analog signal and supplied to the display 23, and if the display 23 is a color display, it is converted to a color signal corresponding to the digital value of the output of the main memory. The signal is supplied to the display 23.

The received signal stored in the buffer memory 17 is a signal on polar coordinates corresponding to the detection direction and the distance from the point of emission to the point of reception, while the signal supplied to the display 23 is a signal on orthogonal coordinates that scans the display surface horizontally and vertically. This is the signal above. Therefore, buffer memory 17
The signals are coordinate-transformed and transferred and stored in the main memory 27.

For this reason, an angle memory 28 is provided in this invention. For example, as shown in FIG. 3, the angle memory 28 stores sine values and cosine values alternately and sequentially for each fixed angle in the direction of orientation of the antenna 11, for example, every 0.17 degrees. This angle memory 28 is read out twice for each pulse wave transmission, and the value corresponding to the angle is read out twice. In other words, the angle memory 28 is read out twice between the time the received signal 22 corresponding to the immediately preceding pulsed radio wave is written in the buffer memory and the end of the transmission of the next pulsed radio wave. In this example, the angle memory 28 is read out at the leading edge and the trailing edge of the trigger pulse 21, respectively. A pulse that rises at the leading edge of the angle pulse generator 19 (Fig. 2 E) is supplied to the angle counter 31 through the OR circuit 29 to increment the angle counter 31, and also rises at the trailing edge of the transmission trigger pulse 21. A pulse (FIG. 2F) is supplied from the transmission trigger generator 13 to the angle counter 31 through the OR circuit 29. OR circuit 2
The angle counter 31 counts the pulses supplied from the angle counter 9. The angle counter 31 is reset when the antenna pointing direction is directed toward a reference direction (for example, toward the bow). Therefore, the count value of the angle counter 31 corresponds to the directional direction of the antenna 11, two different count values are taken for each directional direction, and the angle memory 28 is read out using the angle counter 31 as an address. The first read value, in the example of FIG. 3 the sine value of the angle, is latched into the latch circuit 32 in synchronization with the readout;
The next read value, ie the cosine value of that angle, remains output from the angle memory 28. That is, for example, when the directivity direction of the antenna is 0°, the sine value of 0° is held in the latch circuit 32, and the cosine value of 0° is output from the angle memory 28.

After storing a predetermined number of received signals 22 in the buffer memory 17 as 256 sample values in this example, the contents of the buffer memory 17 are transferred to the main memory 27. A read counter 33 for the buffer memory 17 is provided, and the read counter 33
counts the clocks supplied from the write control section 34 which is controlled by the display control section 24. The count value of the read counter 33 is switched with the count value of the distance counter 18 by the switching circuit 35, and is supplied to the buffer memory 17 as a read address. Further, the counting clock in this read counter 33 is supplied to a write X address generator 36 and a write Y address generator 37, respectively, and at that time, the cosine value read from the angle memory 28 and the sine value held in the latch circuit 32 are calculated. The values are cumulatively added. The cumulative addition values of the X address generator 36 and Y address generator 37 are switched by switching circuits 38 and 39 to read addresses from the read address generators 25 and 26, respectively, and are supplied to the main memory 27 as a write address. be done. Address switching circuits 38, 39
When the main memory 27 is switched to select a write address, the main memory 27 is put into a write state.

The diameter of the PPI display (circular display) on the display 23 is, for example, 512 bits, that is, the number of vertical and horizontal pixels is 512. write address generator 36,
One or more values among the 37 cumulative addition values are supplied to the main memory 27 as an address, and the values below the first place (below the decimal point) are not supplied. In this way, the 256 pieces of data (each data on polar coordinates) received from points sequentially a certain value away from the time of pulse radio wave transmission in a certain angular direction are
It is transferred to the main memory 27 at the (orthogonal) coordinate address location. This can be easily understood from the disclosure in the above-mentioned publication.

Furthermore, in this example, an angle marker signal is also stored at each address of the angle memory 28, using a portion that is redundant for storing sine and cosine values in each word. For example, as shown in FIG.
PPI display is made, and a long angle scale 42 is placed on the periphery of the display circle 41 at intervals of 10 degrees such as 0°, 10°, 20°, etc., and each midpoint between these, i.e.
This is a case where short angle scales 43 are displayed for 5°, 15°, and 25°. For example, the radius of the display circle 41 is 256 bits (pixels), whereas the length of the angle scale 42 is 32 pixels, and the short angle scale 43 is half that length, 16 pixels. In this example, at address positions that are set to constant readout and are not latched by the latch circuit 32, the angles are 0°, 10°, 20°,
As shown in Figure 3, each word corresponding to 30°...in addition to storing the cosine value also stores "1" in the last two bits, corresponding to 5°, 15°, 25°,... Each word that contains a "1" is stored in the second to last bit in addition to its cosine value.

In this example, for the scale 42 at every 30° such as 0°, 30°, etc., if the scale is made thicker, in addition to the cosine value, the address of the four unit angles (0.17°) around that angle is “1” in the last 2 bits
Remember. In order to display the other angle scales thinly, "1" is stored in the second to last bit in addition to the cosine value at each address of one unit angle before and after that angle.

The readings of the storage for these angle markers are each fed to a scale signal generator 44. On the other hand, signals 45 and 46 indicating that the last 16 bits of the read counter 33 and the previous 16 bits are being counted are respectively supplied to the scale signal generator 44. Also, the angle memory 28
The last bit and the bit immediately before it in the read output of each word are supplied to generators 44a and 44b of the scale signal generator 44, respectively. These generators 44a and 44b generate angle scale signals only when both inputs are obtained at the same time, and the synthesis circuit 4
At step 7, the signal is combined with the output of buffer memory 17 and supplied to main memory 27.

Therefore, for example, when the azimuth is 0°, the signal generator 44 of the scale signal generator 44 is output from the angle memory 28.
Since logic 1 is supplied to both a and 44b,
When the reading counter 33 reads the 32nd bit from the end, that is, the count value becomes 224 or more, the generating section 44b,
Angle scale signals are sequentially generated from 44a. Regarding the short angle scale 43, an angle scale signal is generated only from the generator 44b at the corresponding angle, and an angle scale having a length of 16 bits is displayed.

Note that the transfer from the buffer memory 17 to the main memory 27 is generally carried out between displays on the display 23, and for example, in the blanking portion of each horizontal scan, 32 sample values are transferred from the buffer memory 17 in 8 batches. The received signal for one detection is transferred to the main memory.

Note that without providing the buffer memory 17, the received signal 22 is directly transmitted for each transmission trigger, that is,
When transferring the output of the AD converter 16 directly to the main memory 27, the write X address generator 36 and Y address generator 37 are clocked by the distance counter 18.
The output of the AD converter 16 may be written into the main memory 27 while performing the cumulative addition of . Also, at this time, the read counter 37 is changed to the distance counter 18. Furthermore, as mentioned earlier, this idea can be applied not only to radar but also to sonar, etc.

``Effect of the invention'' As mentioned above, according to the coordinate conversion display device of this invention, since the sine value and the cosine value are stored in one angle memory 28, it is possible to effectively use this by using a commercially available read-only memory. can be used. Furthermore, by storing information indicating the angle scale in the angle memory 28 as in the previously described embodiment, the angle memory 28 can be used more effectively.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the coordinate conversion display device according to this invention, FIG. 2 is a time chart for explaining its operation, FIG. 3 is a diagram showing an example of storage in the angle memory 28, and FIG. 4 FIG. 2 is a diagram showing an angle scale on a display. 11: Antenna, 12: Motor, 13: Transmission trigger generator, 14: Transmitter, 15: Receiver, 1
6: AD converter, 17: Buffer memory, 19:
Angle pulse generator, 23: Horizontal/vertical scanning display, 24: Display control section, 25: X address generator for reading, 26: Y address generator for reading, 2
7: Main memory, 31: Angle counter, 28: Angle memory, 33: Reading counter, 36: Writing X address generator, 37: Writing Y address generator, 32: Latch circuit, 35, 38, 39:
Switching circuit, 44: Scale signal generator, 47: Synthesizing circuit.

Claims (1)

[Scope of utility model registration request] A transmitter that repeatedly transmits wave pulses, a receiver that receives reflected waves of the wave pulses, an AD converter that samples the received output of the receiver at a fixed period and converts it into a digital signal, and the digital signal. a buffer memory in which signals are temporarily stored, means for sequentially changing the transmission direction of the wave pulse, means for detecting an angle signal indicating the transmission direction of the wave pulse, and a sine wave value and a cosine wave value of each angle. and an angle memory in which are stored alternately and sequentially, and an angle memory corresponding to the detected angle signal from after the received signal is taken into the buffer memory for each transmission of the wave pulse until the end of transmission of the next wave pulse. reading means for reading out the angle memory twice to obtain the sine wave value and cosine wave value of the angle; a display device for displaying by horizontal and vertical scanning; The main memory and the buffer memory are sequentially read, and each time the sine wave value and the cosine wave value read from the angle memory are cumulatively added, the buffer memory is read to the main memory using these cumulatively added values as an address. A coordinate conversion display device comprising a transfer means for writing output.